Fix unused function warning

Change-Id: I5a0f9d78cf324c98d6be65c535832441d689ab3c
diff --git a/xargs.c b/xargs.c
index b5433c0..f3e99bc 100644
--- a/xargs.c
+++ b/xargs.c
@@ -19,7 +19,6 @@
 static int parsequote(int);
 static int parseescape(void);
 static char *poparg(void);
-static void waitchld(void);
 static void spawn(void);
 
 static size_t argbsz;